The present invention relates generally to systems and methods for deploying stents at one or more treatment sites. More specifically, the invention relates to systems and methods for delivering multiple stents of various lengths to multiple treatment sites using a single device.
Stenting has become an increasingly important treatment option for patients with coronary artery disease. Stenting involves the placement of a tubular prosthesis within a diseased coronary artery to expand the arterial lumen and maintain the patency of the artery. Early stent technology suffered from problems with restenosis, the tendency of the coronary artery to become re-occluded following stent placement. However, improvements in stent design and the advent of drug-eluting stents have reduced restenosis rates dramatically. As a result, the number of stenting procedures being performed in the United States, Europe, and elsewhere has soared.
Stents are delivered to the coronary arteries using long, flexible vascular catheters typically inserted through a femoral artery. For self-expanding stents, the stent is simply released from the delivery catheter and it resiliently expands into engagement with the vessel wall. For balloon expandable stents, a balloon on the delivery catheter is expanded which expands and deforms the stent to the desired diameter, whereupon the balloon is deflated and removed.
Current stent delivery technology suffers from a number of drawbacks. For example, current stent delivery catheters are not capable of customizing the length of the stent in situ to match the size of the lesion to be treated. While lesion size may be measured prior to stenting using angiography or fluoroscopy, such measurements may be inexact. If a stent is introduced that is found to be of inappropriate size, the delivery catheter and stent must be removed from the patient and replaced with a different device of correct size.
Moreover, current stent delivery devices cannot treat multiple lesions with a single catheter. Current devices are capable of delivering only a single stent with a single catheter, and if multiple lesions are to be treated, a new catheter and stent must be introduced for each lesion to be treated.
For these and other reasons, stent delivery systems and methods are needed which enable the customization of stent length in situ, and the treatment of multiple lesions of various sizes, without requiring removal of the delivery catheter from the patient. Such stent delivery systems and methods should further be of minimal cross-sectional profile and should be highly flexible for endovascular positioning through tortuous vascular pathways. Ideally, such stent delivery systems would also allow for accurate and repeatable positioning of one or more stents in a desired position for deployment from a catheter in situ. At least some of these objectives will be met by the present invention.